Wire spool



Sept. 13, 1966 H. R. LANE ETAL 3,272,454

WIRE SPOOL Filed July 22, 1963 5 Sheets-Sheet 1 INVENTORS. Parr/son E45 :78,

Gearye 6 fatten BY WWM .542: twrways Sept. 13, 1966 H. R. LANE ETAL 3,272,454

' WIRE SPOOL Filed July 22, 1963 5 Sheets-Sheet 2 I NVEN TORS I Harv/son ELa/ve,

66 5g -S BY George 6. Tucker,

Sept. 13, 1966 LANE ETAL 3,272,454

WIRE SPOOL Filed July 22, 1963 5 Sheets-Sheet 3 INVENTORS. Warr/san I? Lane, 6290 1986. 7210449 BY W,WM

Mttarnqqs p 13, 1966 H. R. LANE ETAL 3,272,454

WIRE SPOOL Filed July 22, 1965 5 Sheets-Sheet 4 IN VENTORS I Mrrzlsarz E Lane, George 6'. Tucker;

WMv-QM Sept. 13, 1966 H. R. LANE ETAL 3,

WIRE SPOOL Filed July 22, 1963 5 Sheets-Sheet :5

I IN VENTOR. Har /$0)? La ne, George 6. 7216A r',

United States Patent 3,272,454 WIRE SPOOL Harrison R. Lane, Fort Wayne, and George G. Tucker,

Auburn, Ind, assignors to Universal American Corporatlon Filed July 22, 1963, Ser. No. 296,582 18 Claims. (Cl. 242-117) This invention relates generally to spools or reels for accommodating, shipping, and dispensing wire, and more particularly to a spool for precision layer winding of wire.

Wire is commonly wound on spools in random fashion, i.e., a traversing mechanism guides the wire, as it is being wound upon the spool, back and forth across the spool to form successive layers. There are instances, however, where precision winding of the wire on the spool is desired, i.e., with each convolution of each layer cf wire being in engagement with the adjoining convolutions. It is possible, with care, to precision wind the first layer of wire on a spool with each successive convolution tightly against the preceding convolution, however, if the first layer is helically wound in conventional fashion, the convolutions of the second and successive layers of wire cannot be wound in the grooves defined by the convolutions of the preceding layer since the helix of each layer is reversed from that of the preceding layer.

In order to accommodate the maximum amount of wire on a precision wound spool and minimize cross-over bend ing or wire distortion, it is desirable that the convolutions of each layer of wire be seated in the grooves defined by the convolutions of the preceding layer. In order to accomplish this objective, it has been proposed to provide part-annular grooves on the barrel portion of the spool with the respective ends of the grooves being spacedapart to define an axially extending slot across the surface of the spool. Each groove thus locates one convolu tion of the first layer of wire, the axially extending slot accommodating the cross-overs of the wire from one convolution to the next. While this arrangement is satisfactory for the first layer of wire, and while the partannular grooves defined by the convolutions of the first layer locate the convolutions of the second layer, the cross-overs between adjacent convolutions of the second and successive layers take place in an axial line over the cross-overs of the first layer. Since the cross'overs between adjacent convolutions of the second and successive layers inherently are raised slightly above their respective convolutions thus defining an axially extending protuberance or bump, the resulting axially ex tending protuberance in each successive layer of wire is higher than that of the preceding layer; each successive layer is more eccentric than the preceding layer by virtue of its cross-overs which are disposed in axial alignment on top of the cross-overs of the preceding layers. In a full spool of wire thus precision wound, the outermost layer of wire has an axially extending protuberance at the cross-overs of appreciable height, the resulting eccentricity in the wire wound on the spool contributing an undesirable unbalance.

In such spools for precision layer Winding of wire, it is desirable to provide means at the end of the spool opposite from the starting end for guiding the wire as it rises on top of the last convolution of the first layer to form the first return convolution of the second layer. In prior spools for the precision layer winding of wire known to the present applicants, portions have been pro vided at the end of the spool remote from the starting end for performing this function, such portion, however, having a complex configuration including both an axial and a radial lead, thus making the spool difiicult to manufacture in production.

3,272,454 Patented Sept. 13, 1966 Furthermore, in prior spools for the precision layer of wire known to the present applicants, a simple starting hole has been provided in the barrel portion of the spool for accommodating the starting end of the wire. While such an arrangement is satisfactory for wire of small diameter, in larger wire sizes, the starting end of the wire as it leaves the starting hole is formed in a bend which projects radially outwardly beyond the first convolution of the wire, thus forming an objectionable protuberance in the first and successive layers of wire. It is also desirable to provide means for forcing the starting end and thus the first convolution of wire into tight engagement with one head or end flange of the spool thereby to eliminate the necessity for an operator manually to hold the wire tightly against the head.

It is accordingly an object of our invention to provide an improved spool for the precision layer winding of wire.

Another object of our invention is to provide an improved spool for the precision layer winding of wire in which the convolutions of the second and successive layers are respectively located in the grooves defined by adjacent convolutions of the preceding layer.

A further object of our invention is to provide an improved spool for the precision layer winding of wire in which the convolutions of the second and succeeding layers of wire are located in the grooves defined by ad jacent convolutions of preceding layers without an axially extending protuberance being formed at the crossovers of adjacent convolutions.

Yet another object of our invention is to provide an improved spool for the precision layer winding of wire incorporating simple and readily produced means for guiding the wire from the last convolution of the first layer to the first convolution of the second layer.

Still another object of our invention isto provide an improved spool for the precision layer winding of wire wherein the starting end of the wire is secured to the barrel portion of the spool without forming a bend which projects radially outwardly beyond the first convolution.

A still further object of our invention is to provide an improved spool for the precision layer winding of wire wherein the starting end of the wire is automatically forced into tight engagement with the adjacent head.

Further objects and advantages of our invention will become apparent by reference to the following description and the accompanying drawing, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and form.- ing a part of this specification.

In accordance with the broader aspects of the invention, there is provided a spool for precision layer winding of wire having a barrel portion and a pair of head portions respectively at opposite ends of the barrel portion. The barrel portion is provided with a plurality of part-annular grooves formed therein for respectively positioning the convolutions of the first layer of wire on the spool, the respective ends of the grooves being circumferentially spaced-apart and defining a helically extending groove for accommodating the cross-overs of the wire of the first layer between adjacent convolutions. The provision of the helically extending groove accommodates the natural tendency for each cross-over of the first layer to back up slightly with respect to the preceding crossover and further, due to the tendency for the crossovers of successive layers to back up from the cross-overs of preceding layers, distributes the cross-overs of successive layers around the spool in a more uniform fashion thereby eliminating the above-mentioned axially extending eccentric protuberance previously formed by the crossovers of each layer occurring above the cross-overs of the preceding layers.

We have further found that the wire may be guided from the last convolution of the first layer to the first convolution of the second layer by an annular raised portion of uniform width at the end of the spool remote from the starting end.

In accordance with a further aspect of the invention, there is provided a starting hole defined by one head of the spool and by two edges which taper outwardly and divergently toward the one head and which also taper outwardly and divergently away from the starting hole so that the starting end of the wire smoothly joins the first convolution of wire on the barrel portion of the spool without forming a bend which projects radially outwardy beyond the first convolution, and further so that the starting end is wedged into engagement with the one head.

In the drawing:

FIG. 1 is a side elevational view of a wire spool incorporating our invention;

FIG. 2 is a crosssectional view along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view along line 3-3 of.

FIG. 1;

FIG. 4 is a fragmentary enlarged view of the improved starting hole construction of the invention;

FIG. 5 is a fragmentary cross-sectional view taken along the line 55 of FIG. 4;

FIG. 6 is a fragmentary cross-sectional view, showing the winding of the first layer of wire on the spool of FIG. 1;

FIG. 7 is a fragmentary cross-sectional view showing the winding of the second layer of wire on the spool of FIG. 1;

FIG. 8 is a fragmentary cross-sectional view taken along the line 88 of FIG. 7;

FIG. 9 is a fragmentary cross-sectional view showing another embodiment of the invention;

FIG. 10 is a fragmentary crosssectional view taken along the line 10-10 of FIG. 9; and

FIG. 11 is a fragmentary cross-sectional view taken along line 11-11 of FIG. 10.

Referring now to the figures of the drawing, the improved spool for the precision layer winding of wire, generally shown at 10, preferably integrally molded of suitable plastic material, such as polystyrene, comprises a tubular barrel portion 12 and end heads or flanges 14 and 16 at opposite ends of barrel portion 12.

Barrel portion 12 may be connected to arbor tube portion 18 by suitable integral ribs 20 in conventional fashion, as best seen in FIGS. 2 and 3.

A plurality of part-annular grooves 22 of V-shaped cross-section are formed in the barrel portion 12, grooves 22 being respectively defined by part-annular threads 24 which are also of V-shaped cross-sections; grooves 22 and thus threads 24 preferably respectively define angles of ninety degrees (90).

The respective opposite ends 26, 28 of the part-annular threads 24 are circumferentially spaced-apart to define a groove 30 which extends helically across the barrel portion 12 as best seen in FIG. 1. In the preferred embodiment of the invention, groove 30 has a helix angle on the order of forty-five degrees It will be seen that a part-annular half-thread 32 is joined to the inner surface of head 14 to define the first part-annular groove 34.

An annular raised portion 36 is joined to the inner surface of the opposite head 16, raised portion 36 having a uniform width equal to half the width of grooves 22 and threads 24. A part-annular thread 38 is joined to the annular raised portion 36 and defines the last partannular groove 40. The annular raised portion 36 has its outer periphery 42 tapered outwardly toward the head 16 with a slope equal to that of the threads 24 and grooves 22, i.e., forty-five degrees (45 starting at a point spaced above the outer periphery of barrel portion 12, i.e., the

4 points 44 of the threads 24 by the depth of the grooves 22.

Referring particularly to FIGS. 1, 4, and 5, a starting hole 46 is formed in the tubular barrel portion 12 adjacent the starting end head 14 in the helically extending groove 30. Starting hole 46 is defined on one side by the inner surface 48 of flange 14, on the opposite side by a straight edge 50 which is spaced from and parallel with the inner surface 48 of end head 14, and on the remaining sides by straight edges 52 and 54. The straight edges 52 and 54 taper outwardly and divergently from the straight edge 50 toward the inner surface 48 of the head 14 as seen in FIGS. 1 and 4. Thus, when the starting end 56 of the wire being wound on the spool is inserted in the starting hole 46 and tension is exerted thereon in the direction as shown by the arrow 58 in FIG. 4, the wire is wedged outwardly by the tapered edge 54 into tight engagement with the inner surface 48 of the head 14, as shown by the arrow 60 in FIG. 4. It will readily be understood that if the wire were wound on the spool in the opposite direction, the wedging action would be provided by the tapered edge 52.

Referring particularly to FIG. 5, the tapered edges 52, 54 are radially thinner than the radial thickness of the barrel portion 12 and are joined to the inner surface 62 thereof. The tapered edges 52, 54 are respectively joined to the outer peripheral surface of the helically extending groove 39 by surfaces 64-, 66 which respectively taper outwardly and divergently from the opening 46. Thus, it will be seen that the starting end 56 of the Wire being wound on the spool smoothly joins the first convolution 63 without forming a bend which projects radially outwardly beyond the first convolution.

Referring now additionally to FIG. 6, the starting end 56 of the wire to be wound on the spool is positioned in the starting hole 46, as above described, and the first convolution 68 is wound around tthe spool in the first partan'nular groove 34, as shown. When the first convolution 68 reaches the helically extending groove 39, the first cross-over 70 is formed extending across the helical groove 30 and carrying the wire to the second part-annular groove 72, to thus form the second convolution 74. Cross-over 76 carries the wire from the second convolution 74 across the helical groove 30 to the third part-annular groove 78 to form the third convolution 80, and so on.

It will be readily apparent that the part-annular grooves 22 and the part-annular threads 24 are proportioned to accommodate the wire so that each convolution of the first layer intimately engages the adjacent convolutions and with the first convolution 68 intimately engaging the inner surface 48 of the starting end head 14. It Will now be readily seen that the cross-over 76 is nested with crossover 70 and that each successive cross-over is nested with the next preceding cross-over. It will also be readily apparent that by virtue of this nesting of the successive cross-overs, each successive cross-over tends to back up slightly from the next preceding cross-over in the direction shown by the arrow 82. It is this tendency for successive cross-overs to back up which is accommodated by the helical arrangement of the groove 30 on the peripheral surface of the barrel portion .14.

Still referring to FIG. 6, when the last convolution 84 of the first layer of wire in the last part-annular groove 40 reaches cross-over 86 which connects the next-to-last convolution 88 to the last convolution, the wire is forced radially upwardly by the cross-over 86 onto the tapered outer surface 42 of the annular raised portion 36, as at 90. It -will be seen that the tapered outer peripheral surface 42 of the annular raised portion 36 defines a partannular groove with the last convolution 84 of the first layer of Wire which thus locates the first convolution 92 of the second layer in tight engagement with the inner surface of the end head 16.

Referring now additionally to FIG. 7, it will be seen that when the first convolution 92 of the second layer of wire reaches the cross-over 90 which joined the last convolution 84 of the first layer to the first convolution 92 of the second layer, the wire is forced to make cross-over 94 so that the second convolution 96 is located in the partannular groove defined by the adjacent convolutions 4, 88 of the first layer. It will further be observed that cross-over 94 tends to back up slightly in the direction shown by the arrow 98 from the last cross-over 90 of the first layer and that by virtue of the above-described nesting action of the successive cross-overs, the next crossover 100 which joins the second convolution 96 to the third convolution 102 will be backed up sli htly from the first cross-over 94 in the direction shown by the arrow 104, but still will be backed up slightly from the underlying cross-over 86 of the first layer in the direction shown by the arrow 98.

The second layer of wire is thus formed from the head 16 to the head 14 of the spool with each convolution being located in the part-annular groove defined by adjacent convolutions of the first layer and each convolution being in intimate engagement with adjacent convolutions, the cross-overs between convolutions of the second layer of wire following the same helical path as the cross-overs of the first layer, but being backed up therefrom in the direction shown by the arrow 98. The last convolution of Wire of the second layer, as shown by the dashed lines 106 in FIG. 6, is positioned in the part-annular groove defined between the convolutions 68, 74 of the first layer, and this convolution, when reaching the cross-over '70 of the first layer, is forced upwardly and axially into engage ment with the inner surface 48 of the starting end head 14 to form the first convolution of the third layer as shown by the dashed line 108 in FIG. 6.

Referring now particularly to FIG. 8, it is seen that cross-over 112 which joins convolution 110 of the first layer of wire to convolution 88 is defined by reverse bends 114 and 116, respectively. It will further be seen that cross-over 100 which joins convolution 96 of the second layer of wire to convolution 102 is formed by reverse bends 118 and 120, respectively, which are backed up from bends 114, 116 in the direction shown by the arrow 98. Likewise, it will be seen that the cross-over 122 which joins convolutions 124 and 126 of the third layer of wire is defined by reverse bends 128, 1250, respectively, which are likewise backed up from bends 118, 120 of cross-over 100 and bends 114, 116 of crossover 112 in the direction shown by the arrow 98. Thus, while cross-overs 106 and 122 necessarily form a protuberance or bump as they respectively cross-over the underlaying cross-overs, these bumps are progressively displaced circumferentially in the direction shown by the arrow 98. Thus, by virtue of the helical configuration of the groove 30, the bumps resulting from the cross-overs of each successive layer of wire are not cumulatively piled one on top of the other in a single axial line across the spool, but are, on the contrary, circumferenti-ally displaced in a helical pattern and are thus distributed around the spool, thus tending to overcome the eccentric unbalance provided in previous precision layer wound spools incorporating an axially extending groove.

Referring now to FIGS. 9, l0 and 11 in which like elements are indicated by like reference numerals, in order to provide the proper transition of the wire from the second layer to the third layer and thus the requisite precision winding of the third layer with minimum operator attention, it may be desirable to provide means for guiding the wire from the last convolution of the second layer to the first convolution of the third layer; with proper formation of the second and third layers, precision winding of subsequent layers is more readily accomplished. Inspection of FIG. 6 will reveal that such means for guiding the wire as it rises on top of the last convolution 106 of the second layer to form the first return convolution 108 of the third layer cannot conveniently take the form of an annular raised portion on inner surfaces 48 of flange 14 similar to raised portion. 36 on flange 16 since the first convolution 68 of thte first layer of wire is in radial alignment with the first convolution 108 of the third layer and thus, no space is available for such an annular raised portion. However, since the cross-overs of the first and second layers are formed at groove 30, a small space extending radially outwardly from groove 30 adjacent inner surface 48 of flange 14 is available for such guiding means, as seen in FIG. 6 at 138.

Here, starting hole 132 is formed in barrel 12 adjacent inner surface 48 of flange 14 and in groove 30, extending from approximately the transverse center of groove 30 toward ends 26 of threads 24. Starting hole 132 is bounded on its side toward ends 26 of threads 24 by tapered edge 54- joined to the outer surface of groove 30 by tapered surface 66; it will be seen that starting hole 132 with tapered edge 56 and tapered surface 66 is a single sided version of the starting hole 46 of the embodiment of the previous figures.

integrally formed on the inner surface 48 of flange 14 between edge 134 of starting hole 132 and ends 28 of threads 24, and extending radially outwardly from groove 30 is supporting portion 136. As best seen in FIG. 10, the axially outer surface of portion 136 is tapered axially outwardly from inner surface 48 of flange 14 from ends 28 of threads 24 to edge 134 of starting hole 132. Side 137 of supporting portion 136 is flush with edge 134 and has an axial width generally equal to that of the first halfthread 3.... Thus, portion 136 has a generally triangular horizontal cross-section corresponding generally to the triangular space 138 provided between cross-over 70 and inner surface 48 of flange 14, as seen in FIG. 6. Supporting portion 136 has a radially outer surface 140 coaxial with the barrel portion 12 and which is tapered outwardly toward flange 14 with a slope equal to that of threads 24 and grooves 22, i.e., forty-five degrees (45), starting at a point spaced above the outer periphery of barrel portion 12, i.e., the points of threads 24 by two and one half (2 /2) times the depth of the grooves 22.

It will now be seen that when the last convolution 106 of the second layer of wire reaches the last cross-over which connects the next-to-last convolution to the last convolution, the wire will be forced radially upwardly by the last cross-over onto the tapered surface 140 of the supporting portion 136, as at 142.

While the improved spool of our invention has been illustrated and described for use in connection with the precision layer winding of wire, it will be readily apparent that it is equally suitable for the precision layer winding of other elongated strand materials.

It will now be seen that our invention provides an improved spool for the precision layer winding of wire in which the first layer of wire is rapidly and automatically applied in precision fashion thus eliminating the hand operation and close supervision of the operator previously required in order to secure proper formation of the first layer. It is further seen that by virtue of the helically extending groove 30, the bumps in each successive layer of wire inherently provided at the cross-overs between adjacent convolutions are progressively circumferentially displaced in helical fashion rather than being piled up in an axial line as was previously the case. It will further be seen that we have provided means of simple and readily produced configuration for the guiding of the wire from the last convolution of the first layer to the first convolution of the second layer and from the last convolution of the second layer to the first convolution of the third layer. It will further be seen that there is provided in accordance with the invention a starting hole which not only eliminates the bend in the starting end of the wire which projects above the convolutions of the first layer, but which also automatically forces the starting end of the wire into tight engagement with the inner surface of the starting end head of the spool.

While there has been illustrated and described a specific embodiment of the invention, further modifications and improvements will occur to those skilled in the art and we desire therefore in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What is claimed is:

1. A spool for precision layer winding of wire comprising a barrel portion and -a pair of head portions respectively .at opposite ends of said barrel portion, said barrel portion having a plurality of part-annular grooves formed I therein for respectively positioning the convolutions of the first layer of wire on said spool, the respective ends of said grooves being circumferentially spaced-apart, sa-id spaced-apart ends defining a helically extending groove for accommodating the cross-overs of the wire of said first layer between adjacent convolutions.

2. The spool of claim 1 wherein said helically extending groove has a helix angle of approximatealy 45 degrees.

3. The spool of claim 1 further comprising an annular raised portion substantially surrounding said barrel portion and extending radially outwardly therefrom, said raised portion being of uniform axial width and joining one head portion and the said part-annular groove nearest thereto and adapted to define another part-annular groove with the last convolution of said first layer of wire in said nearest part-annular groove thereby locating the first convolution of the second layer of wire.

4. The spool of claim 1 wherein said part-annular grooves are of V-shaped cross-section and respectively defined by part-annular threads of V-shaped cross-section extending axially across said barrel portion between said head portions, a part-annular half-thread joining one head portion and defining the first said part-annular groove with the said part-annular thread nearest said one head portion, and further comprising an annular raised portion substantially surrounding said barrel portion and extending radially outwardly therefrom, said raised portion joining the other head portion and having a uniform axial width of one-half the width of a said part-annular thread, a second part-annular half-thread joining said raised portion and defining the last said part-annular groove with the said part-annular thread nearest said raised portion, the outer periphery of said raised portion tapering outwardly with a slope equal to that of said second halfthread, said raised portion being adapted to define another part-annualr groove with the last convolution of said first layer of wire in said last part-annular groove thereby locating the first convolution of the second layer of wire.

5. The spool of claim 4 wherein said part-annular grooves in said barrel portion are of V-shaped crosssection respectively defining an angle of 90, and wherein said outer periphery of said raised portion tapers outwardly from a point spaced radially outwardly from the outer periphery of said barrel portion by the depth of a said part-annular groove therein.

6. The spool of claim 1 wherein said part-annular grooves are of V-shaped cross-section, the first said partannular groove joining one of said heads and further comprising an annular raised portion joining the other head portion, said raised portion extending radially outwardly beyond the outer periphery of said barrel portion and having a uniform axial width, the last said part-annular groove joining said raised portion, said raised portion being adapted to define another part-annular groove with the last convolution of said first layer of wire in said last part-annular groove thereby locating the first convolution of the second layer of wire.

7. The spool of claim 1 wherein said barrel portion has a starting hole formed therein in said helically extending groove adjacent one head portion for receiving and holding the starting end of the wire to be wound on said spool, said starting hole being defined by at least one surface which tapers inwardly whereby said starting end smoothly joins the first said convolution without forming a bend which projects radially outwardly beyond said first convolution, said surface joining said one head portion and defining an acute angle therewith whereby said starting end is wedge into engagement with said one head portion and retained thereby upon winding tension being exerted thereon.

3. The spool of claim 1 wherein said barrel portion has a starting hole formed therein in said helically extending groove adjacent one head portion for receiving and holding the starting end of the wire to be wound on said spool, said starting hole being defined by said one head portion and by two side edges which respectively join said one head portion and define acute angles therewith whereby said starting end is wedged into engagement with said one head portion and retained thereby upon winding tension being exerted thereon.

9. The spool of claim 8 wherein said two side edges of said starting hole are respectively joined to the outer periphery of said helically extending groove by surfaces which taper outwardly and divergently away from said hole whereby said starting end smoothly joins the first said convolution without forming a bend which projects radially outwardly beyond said first convolution.

10. The spool of claim 1 wherein said barrel portion is tubular and has a starting hole formed therein in said helically extending groove adjacent one head portion for receiving and holding the starting end of the wire to be Wound on said spool, said starting hole being defined on a first side by said one head portion, on a second side by a first straight edge parallel with said one head portion and axially spaced therefrom, and on third and fourth sides by second and third straight edges respectively joining said first straight edge and said one head portion and tapering outwardly and divergently toward said one head portion thereby defining acute angles therewith whereby said starting end is wedged into engagement with said one head portion and retained thereby upon winding tension being exerted thereon, said second and third straight edges respectively being radially thinner than the thickness of said barrel portion and joining the inner surface thereof, said second and third straight edges being respectively joined to the outer periphery of said helically extending grooves by surfaces which taper outwardly and divergently away from said hole whereby said starting end smoothly joins the first said convolution without forming a bend which projects radially outwardly beyond said first convolution.

11. A wire spool having a tubular barrel portion and a pair of head portions respectively at opposite ends of said barrel portion, said barrel portion having a starting hole formed therein adjacent one head portion for receiving and holding the starting end of the wire to be wound on said spool, said starting hole being defined by at least one edge which is radially thinner than the thickness of said barrel portion and joining the inner surface thereof, said edge being joined to the outer peripheral surface of said barrel portion by a surface which tapers outwardly away from said hole whereby said starting end smoothly joins the first convolution of wire on said barrel portion without forming a bend which projects radially outwardly beyond said first convolution, said one edge joining said one head portion and defining an acute angle therewith whereby said starting end is wedged into engagement with said one head portion and retained thereby upon winding tension being exerted thereon.

12. A wire spool having a tubular barrel portion and a pair of head portions respectively at opposite ends of said barrel portion, said barrel portion having a starting hole formed therein adjacent one head portion for receiving and holding the starting end of the wire to be wound on said spool, said starting hole being defined by said one head and by two side edges which respectively divergently join said one head portion and define acute angles therewith whereby said starting end is wedged into engagement with said one head portion and retained thereby upon winding tension being exerted thereon.

13. The spool of claim 12 wherein said two side edges are respectively joined to the outer peripheral surface of said barrel portion by surfaces which taper outwardly and divergently away from said hole whereby said starting end smoothly joins the first convolution of wire on said barrel portion without forming a bend which projects radially outwardly beyond said first convolution.

14. A wire spool having a tubular barrel portion and a pair of head portions respectively at opposite ends of said barrel portion, said barrel portion having a starting hole formed therein adjacent one head portion for receiving and holding the starting end of the wire to be wound on said spool, said starting hole being defined on a first side by said one head portion, on a second side by a first straight edge parallel with said one head portion and axially spaced therefrom, and on third and forth sides by second and third straight edges respectively joining said first straight edge and said one head portion and tapering outwardly and divergent toward said one head portion thereby defining acute angles therewith whereby said starting end is wedged into engagement with said one head portion and retained thereby upon winding tension being exerted thereon, said second and third edges being radially thinner than the thickness of said barrel portion and joining the inner surface thereof, said second and third edges being respectively joined to the outer peripheral surface of said barrel portion by surfaces which taper outwardly and divergently away from said hole whereby said starting end smoothly joins the first convolution of wire on said barrel portion without forming a bend which projects radially outwardly beyond said first convolution.

15. A spool for precision layer winding of wire comprising a barrel portion and a pair of head portions respectively at opposite ends of said barrel portion, said barrel portion having a plurality of part-annular grooves formed therein for respectively positioning the convolutions of the first layer of wire on said spool, the respective ends of said grooves being circumferentially spaced-apart, said spaced-apart ends defining a helically extending groove for accommodating the cross-overs of the wire of said first layer between adjacent convolutions, said barrel portion having a starting hole formed therein in said helically extending groove adjacent one head portion and the ends of said part-annular grooves on one side of said helically extending groove for receiving and holding the starting end of the wire to be wound on said spool, and a supporting portion extending radially outwardly from said helically extending groove between said starting hole and the ends of said part-annular grooves on the other side of said helically extending groove and joining said one head portion for supporting the wire being wound on said spool as it rises from the last convolution of the second layer of wire to the first convolution of the third layer.

16. The spool of claim 15 wherein said barrel portion is tubular and said starting hole is defined on a first side by said one head portion, on a second side by a first straight edge parallel with said one head portion and axially spaced therefrom, on a third side by a straight edge joining said first straight edge and said one head portion and positioned approximately midway between said sides of said helically extending groove, and on a fourth side by a third straight edge joining said first staright edge and said one head portion and tapering outwardly toward said one head portion so that said starting hole is transversely wider adjacent said one head portion than adjacent said first straight edge whereby said starting end is wedged into engagement with said one head portion upon winding tension being exerted thereon, said third edge being radially thinner than the thickness of said barrel portion and joining the inner surface thereof, said third straight edge being joined to the outer periphery of said helically extending groove adjacent said one side thereof by a surface which tapers outwardly away from said hole whereby said starting end smoothly joins the first said convolution without forming a bend which projects radially outwardly beyond said first convolution.

17. The spool of claim 15 wherein said part-annular grooves are of V-shaped cross-section and respectively defined by part-annular threads of V-shaped cross-section extending axially across said barrel portion between said head portions, and wherein a part-annular half-thread joins said one head portion and defines the first said partannular groove with the said part-annular thread nearest said one head portion, said starting hole being defined on a first side by said one head portion and on a second side by a straight edge generally coincident with the axial centerline of said helically extending groove, said supporting portion having an axially outer surface joining said one head adjacent said one side of said helically extending groove and tapering axially outwardly to said straight edge of said starting hole whereby said supporting portion has a generally triangular horizontal cross-section, said supporting portion having a side surface extending radially from said straight edge of said starting hole and having an axial width generally equal to the axial width of said half-thread, said supporting portion having an outer surface coaxial with said barrel portion and tapering outwardly to said one head with a slope equal to that of said half-thread.

18. The spool of claim 17 further comprising an annular raised portion extending radially outwardly beyond said barrel portion, said raised portion joining the other head portion and having a uniform axial width of onehalf the width of a said part-annular thread, a second partannular half-thread joining said raised portion and defining the last said part-annular groove with the said partannular thread nearest said raised portion, the outer periphery of said raised portion tapering outwardly with a slope equal to that of said second half-thread, said raised portion being adapted to define another part-annular groove with the last convolution of said first layer of wire in said last part-annular groove thereby locating the first convolution of the second layer of wire.

References Cited by the Examiner UNITED STATES PATENTS 1,437,987 12/1922 Miller 242-117 1,913,508 6/1933 Phillips 242-117 2,204,938 6/1940 Le Bus 242-1 17 2,732,150 1/1956 Le Bus 242117 2,855,162 10/1958 Schact 242-117 2,892,598 6/1959 Dudley 242-117 FRANK I. COHEN, Primary Examiner. MERVIN STEIN, Examiner.

G. F. MAUTZ, Assistant Examiner. 

1. A SPOOL FOR PRECISION LAYER WINDING OF WIRE COMPRISING A BARREL PORTION AND A PAIR OF HEAD PORTIONS RESPECTIVELY AT OPPOSITE ENDS OF SAID BARREL PORTION, SAID BARREL PORTION HAVING A PLURALITY OF PART-ANNULAR GROOVES FORMED THEREIN FOR RESPECTIVELY POSITIONING THE CONVOLUTIONS OF THE FIRST LAYER OF WIRE ON SAID SPOOL, THE RESPECTIVE ENDS OF SAID GROOVES BEING CIRCUMFERENTIALLY SPACED-APART, SAID SPACED-APART ENDS DEFINING A HELICALLY EXTENDING GROOVE FOR ACCOMMODATING THE CROSS-OVERS OF THE WIRE OF SAID FIRST LAYER BETWEEN ADJACENT CONVOLUTIONS. 